Video tape record cassettes are commonly distributed on a rental basis. It is therefore important to be able to determine the number of times a taped program is displayed, both for calculating the rental fee and for anticipating wear or deterioration of the tape.
Attempts have previously been made to determine playing time of video cassettes. U.S. Pat. No. 3,604,624 connects an incremental indicator to the drive shaft of the recorder for indicating the time of play during a single showing. A pivoted pointer mounted between the reels and contacting the tape on one reel is used in U.S. Pat. No. 3,630,170 to measure the time of play. U.S. Pat. No. 3,678,215 counts the number of times the cassette is inserted into and removed from the recorder. A pivoted sensing arm riding against the reeled tape advances a digital counter in U.S. Pat. No. 3,995,319.